# File lib/phusion_passenger/abstract_server_collection.rb, line 194
        def register_activity(server)
                must_be_in_synchronize_block
                if eligable_for_cleanup?(server)
                        if server.next_cleaning_time == @next_cleaning_time
                                @next_cleaning_time = nil
                        end
                        server.next_cleaning_time = Time.now + server.max_idle_time
                end
        end